EXPLAINER | The Marcellus Shale, Explained
860 stories

The Marcellus Shale, Explained

Scott Detrow / StateImpact Pennsylvania

Marcellus Shale wells flare in Tioga County. When a test well is drilled and there are no pipelines to carry the gas, the gas is burned.

Marcellus Shale is a sedimentary rock buried thousands of feet beneath the earth’s surface.

It stretches from upstate New York south through Pennsylvania to West Virginia and west to parts of Ohio. Named after a town in upstate New York, the rock itself is millions of years old, formed from mud and organic material.

The natural gas created over millions of years as a byproduct of decomposition is trapped in tiny spaces and fissures within the rock. The Marcellus Shale is just one of many shale formations across the world.

When industry speaks of tapping shale gas, it often refers to it as a “shale play.” The Marcellus is one of the first shale plays to be tapped, after the Barnett Shale formation in Texas.

Click on the image to view StateImpact Pennsylvania’s interactive drilling app” credit=”

But how do you know who’s drilling where? StateImpact’s interactive app answers that question, by tracking every single Marcellus Shale well in Pennsylvania. The app tells you who owns each well, what violations drillers have been cited for, and allows you to read articles we’ve published about drilling near the site’s location.

The interactive map allows users to search for wells by company or location, and includes a separate map devoted to tracking what violations are happening where.

StateImpact Pennsylvania

The Shale Play app tracks drillers’ violations.

Each well has its own specific URL you can link to or share via Twitter and Facebook. If you think there’s more we need to know about the drilling site, there’s a space for you to share comments, stories or pictures.

Our app is based on data from DEP’s website. The department updates production information twice a year, and refreshes violation reports about once a month. Data covering the first six months of 2012 became available in mid-August; the next update will come in February.

Some context on the app’s information: StateImpact Pennsylvania initially only tracked wells that were actively producing gas. In June 2012, we updated the app to display every drilled well. That gives a more accurate portrayal of drilling activity.

Latest stories


This active drill site on state forest land in Tioga County will tap the Utica Shale formation, Oct. 2019.

Natural gas production headed for a slow-down in 2020

Pennsylvania, Ohio and West Virginia accounted for one third of the country's shale gas production in 2019.
By Susan Phillips

This July 27, 2011 file photo shows a farmhouse in the background framed by pipes connecting pumps where the hydraulic fracturing process in the Marcellus Shale was underway at a Range Resources site in Claysville, Pa.

A shale gas drilling rig in Washington, Pa.

Study: Shale gas development has brought economic benefits, but also premature deaths

Carnegie Mellon University study focused on Pennsylvania, Ohio, West Virginia
By Julie Grant/The Allegheny Front

Nurdles on Ferrycraigs Beach on the Firth of Forth, Scotland.

Scotland is turning Pennsylvania shale gas into plastic. But what happens to it next?

Taxes and bans on single use plastics try to combat plastics in the oceans
By Reid Frazier

Ships carrying ethane from Pennsylvania sail the Firth of Forth, a river estuary emptying into the North Sea, to Grangemouth.

Despite Scotland’s fracking ban, imported American shale gas is key to the economy in one town. To some, it’s an uneasy state of affairs

One man who grew up near a major petrochemical plant thinks it’s a devil’s bargain: “Why should a community in America have to suffer what we’ve fought hard against?”

By Reid Frazier

President Donald Trump speaks at the 9th annual Shale Insight Conference at the David L. Lawrence Convention Center, Wednesday, Oct. 23, 2019, in Pittsburgh.

President Trump rips Paris climate agreement, Democrats while in Pittsburgh

He touted his administrations deregulation as key to American economic growth.

By Chris Potter/WESA

George Watson's natural gas wells on his Center Township, Greene County land put him at the head of a global supply chain that stretches to Europe and other parts of the world.

Shale gas off-ramp: Pa.’s fracking boom produces a glut of ethane that’s helping fuel plastics production overseas

The path of a global supply chain often begins on land in western Pennsylvania and winds up half a world away, as the plastics industry increasingly relies on dirt-cheap American shale gas to feed its chemical plants and the globe’s growing hunger for plastics.

By Reid Frazier

This 2008 file photo shows a view of the INEOS refinery at Grangemouth, Scotland, where ethane imported from Pennsylvania is processed and turned into plastic.

In Scotland, a town evolved with its refinery. Shale gas arrived to help the plant, but the town could benefit more, one resident says

Dispatches from Scotland, part 4: Grangemouth’s economy leans on the refinery there, and a business owner said she’s learned to accept living near the plant. But, she said, the town ‘should be more vibrant.’

By Reid Frazier

Zoe Shipton, professor of Geology, inside her office at the University of Strathclyde in Glasgow, holding a pseudotachylite from California.

In the UK, fracking is not a thing — so shale gas from the U.S. has become their workaround

Dispatches from Scotland, part 3: StateImpact Pennsylvania’s Reid Frazier talks to a University of Strathclyde professor about how it’s hard to tell how much gas is in Britain’s shale, in part because fracking generally gets a thumbs-down there.

By Reid Frazier

Kevin Ross, president of the Scottish Plastic and Rubber Association, in front of the INEOS Grangemouth refinery and chemical plant.

At Grangemouth refinery in Scotland, a plastics evangelist says U.S. shale gas is vital

Dispatches from Scotland, part 2: StateImpact Pennsylvania’s Reid Frazier talks with Kevin Ross, who runs a company that focuses on plastics testing and recycling and says U.S. shale gas is driving important investment into the UK economy.

By Reid Frazier
LOAD MORE